Semiconductor device and method for fabricating the same

ABSTRACT

A semiconductor device includes a memory block including a transistor region and a memory region. A variable resistance layer of the memory region acts as a gate insulating layer in the transistor region.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of U.S. patent application Ser. No.12/982,122 filed on Dec. 30, 2010, which claims priority of KoreanPatent Application No. 10-2010-0068245, filed on Jul. 15, 2010. Thedisclosure of each of the foregoing applications is incorporated hereinby reference in its entirety.

BACKGROUND OF THE INVENTION

Exemplary embodiments of the present invention relate to semiconductordevice fabrication technology, and more particularly, to a semiconductordevice having a resistive memory and a method for fabricating the same.

Extensive research is being conducted on next-generation memory devicesthat can replace dynamic random access memory (DRAM) devices and flashmemory devices. Examples of the next-generation memory devices includeresistive memory (ReRAM) devices. The resistive memory devices providegood characteristics at low fabrication costs. In particular, theresistive memory devices are esteemed as high-capacity memory devicesbecause they have a very simple stacked structure ofmetal-insulator-metal.

A stacked structure, including a plurality of crossbar type memoryarrays, is especially esteemed as a structure for a high-capacity memorydevice using a resistive memory device.

However, implementing a high-capacity memory device by stacking aplurality of memory arrays requires interconnections and contacts forconnecting the memory array of each layer to peripheral circuits such asa driver and a sense amplifier (SA) formed on a substrate. Theseinterconnections and contacts increase the size of a semiconductordevice and degrade the operation characteristics.

Specifically, in order to form the contacts for connecting the memoryarray of each layer to the peripheral circuits, a separate space for thecontacts should be prepared at the center or the edge of the memoryarray of each layer, thus increasing the size of the semiconductordevice. Also, the structure of interconnections for connection of thecontacts formed in a plurality of layers is complicated and the spaceoccupied for forming the interconnections is increased, thus furtherincreasing the size of the semiconductor device.

Also, as a design rule decreases, the critical dimension of aninterconnection decreases, thus increasing the resistance of theinterconnection. The increase in the resistance of the interconnectionmay cause a loading resistance to be connected to the resistive memorydevice, thus making it difficult to accurately control the resistivememory device formed in each layer.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention are directed to asemiconductor device and a method for fabricating the same, which canreduce the size of a high-capacity memory device.

In accordance with an exemplary embodiment of the present invention, asemiconductor device includes a plurality of memory blocks including atransistor region and a memory region, wherein a variable resistancelayer of the memory region acts as a gate insulating layer in thetransistor region. The memory blocks may be stacked on a substrateincluding a predetermined structure, and an interlayer dielectric may beinserted between the memory blocks.

The variable resistance layer and the gate insulating layer may beconnected to each other, or may be disconnected from each other.

The memory region may include a plurality of first conductive linesdisposed on an interlayer dielectric under the variable resistancelayer, and a plurality of second conductive lines disposed on thevariable resistance layer crossing over the first conductive lines.

The transistor region may include a plurality of gate electrodesdisposed on an interlayer dielectric under the gate insulating layer, achannel layer disposed on the gate insulating layer to overlap the gateelectrodes, and a plurality of source electrodes and drain electrodesdisposed on the channel layer to overlap a portion of the gateelectrodes. The channel layer may include an oxide layer or a siliconlayer. The oxide layer may include at least one material selected fromthe group consisting of an indium oxide layer, a zirconium oxide layer,a gallium oxide layer, and a tin oxide layer. The variable resistancelayer may include an oxide layer, and the oxide layer may include aplurality of oxygen vacancies.

In accordance with another exemplary embodiment of the presentinvention, a semiconductor device includes a plurality of memory blocksincluding a transistor region and a memory region, wherein a variableresistance layer of the memory region has a sequential stack structureof a first insulating layer and a second insulating layer, the firstinsulating layer acts as a gate insulating layer in the transistorregion, and the second insulating layer acts as a channel layer in thetransistor region. The memory blocks may be stacked on a substrateincluding a predetermined structure, and an interlayer dielectric may beinserted between the memory blocks.

The first insulating layer and the gate insulating layer may beconnected to each other, or may be disconnected from each other. Thesecond insulating layer and the channel layer may be connected to eachother, or may be disconnected from each other.

The memory region may include a plurality of first conductive linesdisposed on an interlayer dielectric under the first insulating layer,and a plurality of second conductive lines disposed on the secondinsulating layer crossing over the first conductive lines.

The transistor region may include a plurality of gate electrodesdisposed on an interlayer dielectric under the gate insulating layer,and a plurality of source electrodes and drain electrodes disposed onthe channel layer to overlap a portion of the gate electrodes. The firstinsulating layer and the second insulating layer may include an oxidelayer, and the oxide layer may include a plurality of oxygen vacancies.The second insulating layer may include at least one material selectedfrom the group consisting of an indium oxide layer, a zirconium oxidelayer, a gallium oxide layer, and a tin oxide layer.

In accordance with still another exemplary embodiment of the presentinvention, a semiconductor device includes a transistor, and a memorycell, wherein a variable resistance layer of the memory cell is the samematerial and on the same plane as a gate insulating layer of thetransistor.

In accordance with yet another exemplary embodiment of the presentinvention, a method for fabricating a semiconductor device includesforming an interlayer dielectric defining a transistor region and amemory region forming a plurality of gate electrodes on the interlayerdielectric in the transistor region and forming a plurality of firstconductive lines on the interlayer dielectric in the memory region,forming a first insulating layer on the interlayer dielectric, forming asecond insulating layer on the first insulating layer, forming a firstelectrode and a second electrode on the second insulating layer in thetransistor region to overlap a portion of the gate electrode and forminga plurality of second conductive lines crossing over the firstconductive lines in the memory region, and applying a bias voltage tothe first and second conductive lines to perform a conductive pathforming process.

The method may further include exposing the first insulating layer ofthe memory region by selectively etching the second insulating layer,after the forming of the second insulating layer.

The method may further include dividing the second insulating layer ofthe transistor region and the second insulating layer of the memoryregion by selectively etching the second insulating layer, after theforming of the second insulating layer.

The method may further include dividing the first insulating layer ofthe transistor region and the first insulating layer of the memoryregion by selectively etching the first insulating layer, after theforming of the second insulating layer.

The first insulating layer and the second insulating layer may includean oxide layer, and the oxide layer may include a plurality of oxygenvacancies. The second insulating layer may include at least one materialselected from the group consisting of an indium oxide layer, a zirconiumoxide layer, a gallium oxide layer, and a tin oxide layer.

In accordance with still another exemplary embodiment of the presentinvention, a method for fabricating a semiconductor device includesforming a variable resistance layer in a memory region of a memoryblock, and forming a gate insulating layer in a transistor region of thememory block, wherein the variable resistance layer and the gateinsulating layer are simultaneously formed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view illustrating a semiconductor device inaccordance with a first exemplary embodiment of the present invention.

FIG. 1B is a partial perspective view illustrating one memory block inaccordance with the first exemplary embodiment of the present invention.

FIG. 1C shows cross-sectional views taken along lines A-A′ and B-B′ ofFIG. 1B.

FIG. 2A is a perspective view illustrating a semiconductor device inaccordance with a second exemplary embodiment of the present invention.

FIG. 2B is a partial perspective view illustrating one memory block inaccordance with the second exemplary embodiment of the presentinvention.

FIG. 2C shows cross-sectional views taken along lines A-A′ and B-B′ ofFIG. 2B.

FIG. 3A is a perspective view illustrating a semiconductor device inaccordance with a third exemplary embodiment of the present invention.

FIG. 3B is a partial perspective view illustrating one memory block inaccordance with the third exemplary embodiment of the present invention.

FIG. 3C shows cross-sectional views taken along lines A-A′ and B-B′ ofFIG. 3B.

FIGS. 4A to 4D are perspective views illustrating a method forfabricating a semiconductor device in accordance with an exemplaryembodiment of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Exemplary embodiments of the present invention will be described belowin more detail with reference to the accompanying drawings. The presentinvention may, however, be embodied in different forms and should not beconstrued as limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the present invention tothose skilled in the art. Throughout the disclosure, like referencenumerals refer to like parts throughout the various figures andembodiments of the present invention.

The drawings are not necessarily to scale and in some instances,proportions may have been exaggerated in order to clearly illustratefeatures of the embodiments. When a first layer is referred to as being“on” a second layer or “on” a substrate, it not only refers to a casewhere the first layer is formed directly on the second layer or thesubstrate, but also a case where a third layer exists between the firstlayer and the second layer or the substrate.

The present invention provides a semiconductor device and a method forfabricating the same, which can effectively reduce the size of ahigh-capacity memory device. To this end, the present invention providesa semiconductor device integrating a peripheral circuit and a resistivememory device in which a plurality of memory blocks are stacked and eachmemory block has a crossbar type array structure. Herein, the peripheralcircuit includes a driver for driving the resistive memory device and asense amplifier (SA) for detecting stored data. As is well known in theart, a peripheral circuit such as a sense amplifier includes a pluralityof transistors and is configured with a combination thereof.

Hereinafter, for convenience in description, a description will be givenof exemplary embodiments in which a semiconductor device has a stackstructure of three memory blocks. However, the present invention is notlimited thereto. That is, in other exemplary embodiments, asemiconductor device may have a stack structure with less than or morethan three memory blocks.

FIGS. 1A to 1C are views illustrating a semiconductor device inaccordance with a first exemplary embodiment of the present invention.FIG. 1A is a perspective view illustrating a semiconductor device inaccordance with a first exemplary embodiment of the present invention.FIG. 1B is a partial perspective view illustrating one memory block inaccordance with the first exemplary embodiment of the present invention.FIG. 1C shows cross-sectional views taken along lines A-A′ and B-B′ ofFIG. 1B.

Referring to FIGS. 1A to 1C, a semiconductor device in accordance withthe first exemplary embodiment of the present invention includes asubstrate 101 having a predetermined structure formed therein, aplurality of memory blocks 102 stacked on the substrate 101, and apassivation layer 103 formed on the top layer.

The substrate 101 may include various semiconductor devices such as apower device, a high voltage device, a display driver IC (DDI) device,and a bipolar-CMOS-DMOS (BCD) device.

Each of the memory blocks 102 has a transistor region where a peripheralcircuit is formed, and a memory region where a resistive memory deviceis formed. In the first exemplary embodiment of the present invention, avariable resistance layer 13A of the memory region acts as a gateinsulating layer 13B in the transistor region. That is, the variableresistance layer 13A and the gate insulating layer 13B aresimultaneously formed of the same material and are disposed on the sameplane. As illustrated in FIG. 1B, the variable resistance layer 13A maybe connected to the gate insulating layer 13B. Although not illustratedin the drawings, in other embodiments, the variable resistance layer 13Aand the gate insulating layer 13B may not be connected to each other.

The memory region includes an interlayer dielectric 11, a plurality offirst conductive lines 12A formed on the interlayer dielectric 11 to actas a bottom electrode (BE), a variable resistance layer 13A formed onthe interlayer dielectric 11 to contact the first conductive lines 12A,and a plurality of second conductive lines 15A formed on the variableresistance layer 13A to act as a top electrode (TE). The secondconductive lines 15A are arranged so that they cross over the firstconductive lines 12A. That is, a resistive memory device formed in thememory region has a crossbar type array structure where the variableresistance layer 13A is disposed between the crossing first and secondconductive lines 12A and 15A.

The transistor region includes an interlayer dielectric 11, a pluralityof gate electrodes 12B formed on the interlayer dielectric 11, a gateinsulating layer 13B formed on the interlayer dielectric 11 to contactthe gate electrodes 12B, a channel layer 14 formed on the gateinsulating layer 13B to overlap the gate electrodes 12B, and firstelectrodes (or drain electrodes) 15B and second electrodes (or sourceelectrodes) 15C formed on the channel layer 14 to overlap a portion ofcorresponding gate electrodes 12B. Herein, the first electrodes 15B maybe connected to corresponding second conductive lines 15A of the memoryregion.

The variable resistance layer 13A of the memory region extends to thetransistor region to act as the gate insulating layer 13B. Therefore,the variable resistance layer 13A of the memory region and the gateinsulating layer 13B of the transistor region may be formed of the samematerial. Also, the variable resistance layer 13A and the gateinsulating layer 13B are simultaneously formed through the same process,and are disposed on the same plane. Also, the variable resistance layer13A and the gate insulating layer 13B have a thickness of approximately1 nm to approximately 100 nm.

The variable resistance layer 13A may be an oxide layer including aplurality of oxygen vacancies. Herein, the oxygen vacancies serve tochange the resistance of the variable resistance layer 13A.Specifically, the variable resistance layer 13A has a conductive pathcreated by the oxygen vacancies through a conductive path formingprocess that rearranges the oxygen vacancies by applying a high voltageto the first conductive line 12A and the second conductive line 15A.Whether or not an operation voltage (lower than the high voltage appliedin the conductive path forming process) is applied to the firstconductive line 12A and the second conductive line 15A determineswhether or not the conductive path connects the first conductive line12A and the second conductive line 15A. In this manner, the resistanceof the variable resistance layer 13A may be changed and the change maybe used to store data.

Since the variable resistance layer 13A and the gate insulating layer13B are formed of the same material, the gate insulating layer 13B alsoincludes a plurality of oxygen vacancies. Even when the gate insulatinglayer 13B includes a plurality of oxygen vacancies, because theconductive path by the oxygen vacancies is not created through theconductive path forming process, it does not have variable resistancecharacteristics like the variable resistance layer 13A. Thus, the gateinsulating layer 13B has insulating characteristics even though itincludes oxygen vacancies like the variable resistance layer 13A formedof the same material.

The variable resistance layer 13 a may include at least one materialselected from the group consisting of silicon (Si) oxide, aluminum (Al)oxide, hafnium (Hf) oxide, zirconium (Zr) oxide, lanthanum (La) oxide,titanium (Ti) oxide, niobium (Nb) oxide, tantalum (Ta) oxide, nickel(Ni) oxide, strontium-titanium (SrTi) oxide, barium-titanium (BaTi)oxide, and barium-strontium (BaSr) oxide.

The first conductive line 12A and the gate electrode 12B disposed on thesame plane may include the same material. Also, the first conductiveline 12A and the gate electrode 12B may be simultaneously formed throughthe same process.

Herein, the first conductive line 12A, the gate electrode 12B, thesecond conductive line 15A, the first electrode 15B, and the secondelectrode 15C may be a metallic layer. The metallic layer may includetungsten (W), tantalum (Ta), platinum (Pt), titanium nitride (TiN), ortantalum nitride (TaN).

The channel layer 14 of the transistor region may have a thickness ofapproximately 1 nm to approximately 100 nm, and may include a siliconlayer or an oxide layer. Herein, the silicon layer may include apolysilicon (poly Si) layer. Also, the oxide layer may include at leastone material selected from the group consisting of indium oxide (In₂O₃),zirconium oxide (ZnO), gallium oxide (Ga₂O₃), and tin oxide (SnO₂). Theoxide layer for the channel layer 14 has semiconductor characteristicsdue to its atomic bond (e.g., metal-oxygen bond). Also, it is know thatthe oxide layer has a wide band gap and a high carrier mobility. Forreference, the wide band gap means a band gap of more than 3.5 eV.

In the semiconductor device in accordance with the first exemplaryembodiment of the present invention, the memory device and theperipheral circuit are integrated in one memory block 102. Accordingly,the present invention does not require a separate interconnection andcontact for connecting the peripheral circuit and the memory device.Therefore, the present invention can provide a high-capacity memorydevice having a reduced chip size. Also, the present invention cansimplify the fabrication process of a high-capacity memory device.

Conventionally, a peripheral circuit for a memory device is formed onthe substrate 101. However, the present invention does not need to forma peripheral circuit for a memory device on the substrate 101. Thus,various semiconductor devices can be formed in a space typically usedfor a peripheral circuit and for interconnections and contacts.Accordingly, an embedded system with a high-capacity memory device canbe constructed with a reduced chip size.

FIGS. 2A to 2C are views illustrating a semiconductor device inaccordance with a second exemplary embodiment of the present invention.FIG. 2A is a perspective view illustrating a semiconductor device inaccordance with the second exemplary embodiment of the presentinvention. FIG. 2B is a partial perspective view illustrating one memoryblock in accordance with the second exemplary embodiment of the presentinvention. FIG. 2C shows cross-sectional views taken along lines A-A′and B-B′ of FIG. 2B.

Hereinafter, for convenience in description, like reference numerals areused to denote like elements throughout the first and second exemplaryembodiments of the present invention.

Referring to FIGS. 2A to 2C, a semiconductor device in accordance withthe second exemplary embodiment of the present invention includes asubstrate 201 having a predetermined structure formed therein, aplurality of memory blocks 202 stacked on the substrate 201, and apassivation layer 203 formed on the top layer.

The memory block 202 has a transistor region where a peripheral circuitis formed, and a memory region where a resistive memory device isformed. In the second exemplary embodiment of the present invention, avariable resistance layer 23 of the memory region acts as a gateinsulating layer 21B and a channel layer 22B in the transistor region.Specifically, the variable resistance layer 23 has a sequential stack ofa first oxide layer 21A and a second oxide layer 22A, wherein the firstoxide layer 21A acts as the gate insulating layer 21B in the transistorregion and the second oxide layer 22A acts as the channel layer 22B inthe transistor region. That is, the first oxide layer 21A and the gateinsulating layer 21B are simultaneously formed of the same material andare disposed on the same plane. As illustrated in the drawings, thefirst oxide layer 21A may be connected to the gate insulating layer 21B.Also, the second oxide layer 22A and the channel layer 22B aresimultaneously formed of the same material and are disposed on the sameplane. As illustrated in the drawings, the second oxide layer 22A may beconnected to the channel layer 22B.

The memory region includes an interlayer dielectric 11, a plurality offirst conductive lines 12A formed on the interlayer dielectric 11 to actas a bottom electrode (BE), a first oxide layer 21A formed on theinterlayer dielectric 11 to contact the first conductive lines 12A, asecond oxide layer 22A formed on the first oxide layer 21A, and aplurality of second conductive lines 15A formed on the second oxidelayer 22A to act as a top electrode (TE). The second conductive lines15A are arranged so that they cross over the first conductive lines 12A.That is, a resistive memory device formed in the memory region has acrossbar type array structure where the variable resistance layer 23 isdisposed between the crossing first and second conductive lines 12A and15A.

The transistor region includes an interlayer dielectric 11, a pluralityof gate electrodes 12B formed on the interlayer dielectric 11, a gateinsulating layer 21B formed on the interlayer dielectric 11 to contactthe gate electrodes 12B, a channel layer 22B formed on the gateinsulating layer 21B to overlap the gate electrodes 12B, and firstelectrodes (or drain electrodes) 15B and second electrodes (or sourceelectrodes) 15C formed on the channel layer 22B to overlap a portion ofcorresponding gate electrodes 12B. Herein, the first electrodes 15B maybe connected to corresponding second conductive lines 15A of the memoryregion.

The first oxide layer 21A acting as the variable resistance layer 23 inthe memory region extends to the transistor region to act as the gateinsulating layer 21B. Therefore, the first oxide layer 21A and the gateinsulating layer 21B may be formed of the same material. Also, the firstoxide layer 21A and the gate insulating layer 21B are simultaneouslyformed through the same process, and are disposed on the same plane.Also, the first oxide layer 21A and the gate insulating layer 21B have athickness of approximately 1 nm to approximately 100 nm.

The second oxide layer 22A acting as the variable resistance layer 23 inthe memory region extends to the transistor region to act as the channellayer 22B. Therefore, the second oxide layer 22A and the channel layer22B may be formed of the same material. Also, the second oxide layer 22Aand the channel layer 22B are simultaneously formed through the sameprocess, and are disposed on the same plane. Also, the second oxidelayer 22A and the channel layer 22B have a thickness of approximately 1nm to approximately 100 nm.

The first oxide layer 21A and the second oxide layer 22A acting as thevariable resistance layer 23 may include a plurality of oxygenvacancies. Herein, the oxygen vacancies serve to change the resistanceof the variable resistance layer 23. Specifically, the variableresistance layer 23 has a conductive path created by the oxygenvacancies through a conductive path forming process that rearranges theoxygen vacancies by applying a high voltage to the first conductive line12A and the second conductive line 15A. Whether or not an operationvoltage (lower than the high voltage applied in the conductive pathforming process) is applied to the first conductive line 12A and thesecond conductive line 15A determines whether or not the conductive pathconnects the first conductive line 12A and the second conductive line15A. In this manner, the resistance of the variable resistance layer 23may be changed and the change may be used to store data.

Since the gate insulating layer 21B and the channel layer 22B are formedof the same materials as the first oxide layer 21A and the second oxidelayer 22A, respectively, they also may include a plurality of oxygenvacancies. However, even though the gate insulating layer 21B and thechannel layer 22B include a plurality of oxygen vacancies, they do nothave variable resistance characteristics like the variable resistancelayer 23. The gate insulating layer 21B and the channel layer 22B do nothave variable resistance characteristics because the conductive pathforming process is not performed on the oxygen vacancies in thetransistor region, and thus, a conductive path is not created in thetransistor region. Thus, the gate insulating layer 21B and the channellayer 22B maintain their own physical properties even though they areformed of the same material as the variable resistance layer 23, andtherefore include oxygen vacancies. That is, the gate insulating layer21B has insulating characteristics even though it includes oxygenvacancies; and the channel layer 22B has semiconductor characteristicseven though it includes oxygen vacancies.

The gate insulating layer 21B and the first oxide layer 21A may includeat least one material selected from the group consisting of silicon (Si)oxide, aluminum (Al) oxide, hafnium (Hf) oxide, zirconium (Zr) oxide,lanthanum (La) oxide, titanium (Ti) oxide, niobium (Nb) oxide, tantalum(Ta) oxide, nickel (Ni) oxide, strontium-titanium (SrTi) oxide,barium-titanium (BaTi) oxide, and barium-strontium (BaSr) oxide.

The channel layer 22B and the second oxide layer 22A may include atleast one material selected from the group consisting of indium oxide(In₂O₃), zirconium oxide (ZnO), gallium oxide (Ga₂O₃), and tin oxide(SnO₂).

In the semiconductor device in accordance with the second exemplaryembodiment of the present invention, the variable resistance layer 23 ofthe memory region extends to the transistor region to act as the gateinsulating layer 21A and the channel layer 22B. Accordingly, the secondexemplary embodiment of the present invention can simplify thefabrication process and the structure of the semiconductor device.

FIGS. 3A to 3C are views illustrating a semiconductor device inaccordance with a third exemplary embodiment of the present invention.FIG. 3A is a perspective view illustrating a semiconductor device inaccordance with the third exemplary embodiment of the present invention.FIG. 3B is a partial perspective view illustrating one memory block inaccordance with the third exemplary embodiment of the present invention.FIG. 3C shows cross-sectional views taken along lines A-A′ and B-B′ ofFIG. 3B.

Hereinafter, for convenience in description, like reference numerals areused to denote like elements throughout the second and third embodimentsof the present invention.

As illustrated in FIGS. 3A to 3C, a semiconductor device in accordancewith the third exemplary embodiment of the present invention is similarto the semiconductor device in accordance with the second exemplaryembodiment of the present invention.

As shown in FIGS. 3A to 3C, the channel layer 22B in the transistorregion is disconnected from the second oxide layer 22A acting as avariable resistance layer 23 in the memory region. Although the secondoxide layer 22A and the channel layer 22B are disconnected from eachother, they are simultaneously formed of the same material and aredisposed on the same plane.

Although not illustrated in the drawings, the first oxide layer 21A andthe gate insulating layer 21B may be disconnected from each other aswell. Where the first oxide layer 21A and the gate insulating layer 21Bare disconnected from each other, they still may be simultaneouslyformed of the same material and disposed on the same plane.

FIGS. 4A to 4D are perspective views illustrating a method forfabricating a semiconductor device in accordance with an exemplaryembodiment of the present invention.

Herein, as an example, a description will be given of a method forfabricating a semiconductor device having the structure in accordancewith the second exemplary embodiment of the present invention. From thisdescription, similar methods for fabricating other exemplary embodimentsshould be understood.

Referring to FIG. 4A, an interlayer dielectric 31, having a transistorregion and a memory region, is selectively etched to form a first recesspattern 32 in the memory region and form a second recess pattern 33 inthe transistor region.

Referring to FIG. 4B, a conductive layer is deposited on the interlayerdielectric 31 to fill the first and second recess patterns 32 and 33.After the deposition of the conductive layer, a planarization processmay be performed to expose the interlayer dielectric 31. Theplanarization process may be performed through a chemical mechanicalpolishing (CMP) process.

Through the above process, first conductive lines 34A filling the firstrecess pattern 32 and acting as bottom electrodes are formed in thememory region. Also, gate electrodes 34B filling the second recesspattern 33 are formed in the transistor region. Herein, the firstconductive lines 34A and the gate electrodes 34B may include a metalliclayer. The metallic layer may include tungsten (W), tantalum (Ta),platinum (Pt), titanium nitride (TiN), or tantalum nitride (TaN).

Referring to FIG. 4C, a first insulating layer 35 is formed over theinterlayer dielectric 31 including the first conductive lines 34A andthe gate electrodes 34B. Herein, the first insulating layer 35 acts as avariable resistance layer in the memory region, and acts as a gateinsulating layer in the transistor region.

The first insulating layer 35 may include an oxide layer includingoxygen vacancies. Specifically, the first insulating layer may be formedof at least one material selected from the group consisting of silicon(Si) oxide, aluminum (Al) oxide, hafnium (Hf) oxide, zirconium (Zr)oxide, lanthanum (La) oxide, titanium (Ti) oxide, niobium (Nb) oxide,tantalum (Ta) oxide, nickel (Ni) oxide, strontium-titanium (SrTi) oxide,barium-titanium (BaTi) oxide, and barium-strontium (BaSr) oxide.

A second insulating layer 36 is formed on the first insulating layer 35.Herein, the second insulating layer 36 acts as a variable resistancelayer in the memory region in combination with the first insulatinglayer 35, and acts as a channel layer in the transistor region.

The second insulating layer 36 may include an oxide layer that containsoxygen vacancies and semiconductor characteristics. Specifically, thesecond insulating layer 36 may be formed of at least one materialselected from the group consisting of indium oxide (In₂O₃), zirconiumoxide (ZnO), gallium oxide (Ga₂O₃), and tin oxide (SnO₂).

After the second insulating layer 36 is formed, the second insulatinglayer 36 may be selectively etched to expose the first insulating layer35 in the memory region, thereby forming the structure in accordancewith the first exemplary embodiment of the present invention. After thesecond insulating layer 36 is selectively etched, the first insulatinglayer 35 may be selectively etched to divide the first insulating layer35 of the transistor region and the first insulating layer 35 of thememory region.

Alternatively, after the second insulating layer 36 is formed, thesecond insulating layer 36 may be selectively etched to divide thesecond insulating layer 36 of the transistor region and the secondinsulating layer 36 of the memory region, thereby forming the structurein accordance with the third exemplary embodiment of the presentinvention. Herein, after the second insulating layer 36 is selectivelyetched, the first insulating layer 35 may be selectively etched todivide the first insulating layer 35 of the transistor region and thefirst insulating layer 35 of the memory region.

Referring to FIG. 4D, a conductive layer is deposited on the secondinsulating layer 36 and the conductive layer is selectively etched toform at least one second conductive line 37A acting as a top electrodeof the memory region. While the second conductive line 37A, crossingover the first conductive lines 34A, is formed, a first electrode 37Band a second electrode 37C, acting as a source electrode and a drainelectrode, are formed in the transistor region.

Herein, the second conductive line 37A, the first electrode 37B, and thesecond electrode 37C may include a metallic layer. The metallic layermay include tungsten (W), tantalum (Ta), platinum (Pt), titanium nitride(TiN), or tantalum nitride (TaN).

A high voltage is applied to the first conductive line 34A and thesecond conductive line 37A to perform a conductive path forming processthat creates a conductive path using oxygen vacancies in the first andsecond insulating layers 35 and 36 formed in the memory region.

One memory block can be completed by the above processes. The aboveprocesses may be repeated to stack memory blocks on the substrate,thereby completing a semiconductor device with a high-capacity memorydevice.

As described above, the present invention integrates a memory region anda transistor region, which is used to drive the memory device, in onememory block. Accordingly, the present invention does not require aseparate interconnection and contact for connecting the peripheralcircuit and the memory device. Therefore, the present invention canimplement a high-capacity memory device with a reduced chip size.

While the present invention has been described with respect to thespecific embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the invention as defined in the followingclaims.

What is claimed is:
 1. A method for fabricating a semiconductor device,comprising: forming an interlayer dielectric defining a transistorregion and a memory region; forming a plurality of gate electrodes onthe interlayer dielectric in the transistor region and forming aplurality of first conductive lines on the interlayer dielectric in thememory region; forming a first insulating layer on the interlayerdielectric; forming a second insulating layer on the first insulatinglayer; and forming a first electrode and a second electrode on thesecond insulating layer in the transistor region to overlap a portion ofthe gate electrode and forming a plurality of second conductive linescrossing over the first conductive lines in the memory region.
 2. Themethod of claim 1, further comprising: exposing the first insulatinglayer in the memory region by selectively etching the second insulatinglayer, after the forming of the second insulating layer.
 3. The methodof claim 1, further comprising: dividing the second insulating layer ofthe transistor region and the second insulating layer of the memoryregion by selectively etching the second insulating layer, after theforming of the second insulating layer.
 4. The method of 3, furthercomprising: dividing the first insulating layer of the transistor regionand the first insulating layer of the memory region by selectivelyetching the first insulating layer, after the forming of the secondinsulating layer.
 5. The method of claim 1, wherein the first insulatinglayer and the second insulating layer comprise an oxide layer, and theoxide layer includes a plurality of oxygen vacancies.
 6. The method ofclaim 5, wherein the second insulating layer comprises at least onematerial selected from the group consisting of an indium oxide layer, azirconium oxide layer, a gallium oxide layer, and a tin oxide layer. 7.A method for fabricating a semiconductor device, comprising: forming avariable resistance layer in a memory region of a memory block; andforming a gate insulating layer in a transistor region of the memoryblock, wherein the variable resistance layer and the gate insulatinglayer are simultaneously formed, and wherein the memory regioncomprises: a plurality of first conductive lines disposed on aninterlayer dielectric and under the variable resistance layer; and aplurality of second conductive lines disposed on the variable resistancelayer and crossing over the first conductive lines.
 8. The semiconductordevice of claim 7, wherein the variable resistance layer and the gateinsulating layer are connected to each other.
 9. The semiconductordevice of claim 7, wherein the transistor region comprises: a pluralityof gate electrodes disposed on an interlayer dielectric under the gateinsulating layer; a channel layer disposed on the gate insulating layerto overlap the gate electrodes; and a plurality of source electrodes anddrain electrodes disposed on the channel layer to overlap a portion ofthe gate electrodes.
 10. The semiconductor device of claim 9, whereinthe channel layer comprises an oxide layer or a silicon layer.
 11. Thesemiconductor device of claim 10, wherein the oxide layer comprises atleast one material selected from the group consisting of an indium oxidelayer, a zirconium oxide layer, a gallium oxide layer, and a tin oxidelayer.